1. Field of the Invention
This invention relates to a multicylinder, internal combustion engine of the kind comprising a crankcase secured to a connector flange of the cylinder block and a flywheel arranged at the output end of the crankshaft.
2. The Prior Art
In conventional multicylinder internal combustion engines the dividing plane between the cylinder block and the crankcase is usually situated approximately at the level of the crankshaft axis, and the flywheel housing is usually connected to the cylinder block and the crankcase by a plurality of bolts or screws which extend in a direction parallel to the crankshaft axis. The main bearings of the crankshaft are carried by the two-part, or divided, main bearing walls of the cylinder block and crankcase, or on brackets screwed or bolted to bearing bosses on the cylinder block. This conventional construction design involves comparatively heavy engine weights and a considerable outlay for the necessary casting technique and machining operations used. Furthermore, since engine torque is frictionally transmitted from the cylinder block to the flywheel housing, and in view of the small friction coefficient of about 0.1, numerous fastener bolts or screws of comparatively large cross section are needed on the flywheel flange. (Hereinafter, where the context admits, the term `fastener` is deemed to include screws, bolts, studs or similar threaded elements).
Moreover, owing to the comparatively short distance between the dividing plane of the cylinder block and crankcase and the engine oil level, it is necessary to ensure an extremely careful seal along the connecting flanges of engine block and crankcase.
Finally, with these conventional engines there is also a very high degree of noise emission in the region of the crankshaft through or from the outer walls of the engine block. Consequently, the parts which are mounted on the engine block in the region of the crankshaft, e.g., the oil sump, the flywheel housing, etc., also have a very high level of resonance emission. Accordingly, these conventional combustion engines are also much in need of improvement with regard to noise emission, taken from the point of view of environmental protection.
It is the aim of the present invention to avoid the disadvantages appertaining to conventional constructions of a multicylinder internal combustion engine and to provide an engine of the kind specified which is primarily distinguished by its weight economy and reduced production outlay.